Dr. Young's LabYoung, M.A., Reardon, A., Azam, O. (2008). Rumination and vegetative symptoms: A test of the Dual Vulnerability Model of seasonal depression. Cognitive Therapy and Research, 32:567–576.
The Dual Vulnerability Model of seasonal affective disorder proposes that the cognitive-affective symptoms of seasonal depression are the result of an interaction of a diathesis of cognitive vulnerability to depression and the stressor of seasonal vegetative change. Two studies examined this hypothesis employing a within-subject design with daily data on vegetative and cognitive-affective depressive symptoms. Study 1 included a subclinical sample and a trait measure of ruminative response style. Study 2 included a clinical sample and reports of actual ruminative thoughts and behaviors in response to fatigue. Results of mixed linear model analyses in both studies supported the hypothesis that rumination moderates the relationship between the vegetative symptoms and the cognitive-affective symptoms of seasonal depression. The extension of the model to other subtypes of depression is considered.